function point analysis & estimation

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www.davidconsultinggroup.com

FUNCTION POINT ANALYSIS &

ESTIMATION

Gurpreet Singh

M.Tech CSE Part Time – 3rd Semester

Roll No. 17 & Regd. No. 40800066

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What is Function Point Analysis (FPA)?

• It is designed to estimate and measure the time, and thereby the cost, of developing new software applications and maintaining existing software applications.

• It is also useful in comparing and highlighting opportunities for productivity improvements in software development.

• It was developed by A.J. Albrecht of the IBM Corporation in the early 1980s.

• The main other approach used for measuring the size, and therefore the time required, of software project is lines of code (LOC) – which has a number of inherent problems.

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• Inputs• Outputs• Inquiries• Internal Logical Files• External Interface Files

Input Inquiry

Output

InternalLogical

Files

External Interface

File

Five key components are identified based on logical user view

Application

The Function Point Methodology

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General System CharacteristicsData Communication On-Line Update

Distributed Data Processing Complex Processing

Performance Objectives Reusability

Heavily Used Configuration Conversion & Install Ease

Transaction Rate Operational Ease

On-Line Data Entry Multiple-Site Use

End-User Efficiency Facilitate Change

The final calculation is based upon the Unadjusted FP count X VAF

14 Optional General Systems Characteristics are evaluated and used to compute a Value Adjustment Factor (VAF)

The Function Point Methodology

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What is Function Point Analysis (FPA)?

These function-point counts are then weighed (multiplied) by their degree of complexity:

Simple Average ComplexInputs 2 4 6Outputs 3 5 7Files 5 10 15Inquires 2 4 6Interfaces 4 7 10

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What is Function Point Analysis (FPA)?

A simple example:

inputs3 simple X 2 = 6 4 average X 4 = 161 complex X 6 = 6

outputs6 average X 5 = 302 complex X 7 = 14

files5 complex X 15 = 75

inquiries8 average X 4 = 32

interfaces3 average X 7 = 214 complex X 10 = 40

Unadjusted function points 240

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What is Function Point Analysis (FPA)?

Continuing our example . . . Complex internal processing = 3Code to be reusable = 2High performance = 4Multiple sites = 3Distributed processing = 5

Project adjustment factor = 17

Adjustment calculation:Adjusted FP = Unadjusted FP X [0.65 + (adjustment factor X 0.01)] = 240 X [0.65 + ( 17 X 0.01)] = 240 X [0.82] = 197 Adjusted function points

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PROJECTSIZE

X X RISKFACTORS

PROJECTCOMPLEXITY

DEFINITION CAPABILITY ESTIMATE

Schedule

Effort Costs

REQUIREMENT

FUNCTION POINT ANALYSIS

Project Estimation

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Conclusions

• Project Management can be successful • Requirements can be managed • Projects can be sized • Performance can be successfully estimated • Process improvement can be modeled• Measurement can be accomplished

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Thanks